Hip Extension

How to do it: 

Start on your hands and knees, with your shoulders directly over your hands and your hips over your knees (shown).
Tighten your abdominals and keep them engaged throughout the set.
Lift your left leg into the air until the sole of your shoe is facing the ceiling and your thigh is parallel to the floor.
Slowly lower the knee until it’s hovering just above the floor.
Repetitions: Do eight reps on each side.

Bonus benefits: This move also tightens the abdominals and strengthens the muscles in the lower back.

臀部伸展

如何做到这一点：

双手和膝盖着地，肩部与双手垂直，臀部与膝盖垂直(如图所示）。
整个练习中要收紧腹部。
抬起左腿，直到鞋底面临天花板，保证大腿与地面平行。
慢慢地降低膝盖，回到原位置。
重复：左右腿各重复8次。

好处：收紧腹肌，加强腰腹力量。